Two-Component Development for Thick Organic Photodrums at High Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed image forming apparatuses using a two-component developer with a thick organic photosensitive layer face issues such as discharge unevenness and drum ghost due to narrow operational windows for surface potential and developing voltage settings.
Innovation Solution
Optimize developing conditions by using a low-resistance carrier and controlling developing voltage and frequency to maintain image quality, extending the lifespan of the photosensitive drums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the photosensitive layer thickness is increased to extend apparatus lifespan, then the lifespan is improved, but the tolerance in surface potential and developing voltage settings becomes narrow, causing image problems
Solution Approach 1:
The patent applies parameter changes by optimizing the developing voltage parameters (AC voltage amplitude and DC voltage) specifically for thick photosensitive layers (40 μm or more). By adjusting these electrical parameters, the invention maintains stable image quality despite the reduced tolerance window, thereby resolving the contradiction between extended lifespan and image quality stability.
2Productivity
If the processing linear speed is increased to improve productivity, then the productivity is improved, but the carrier development increases, requiring weaker electric fields
Solution Approach 1:
The patent employs parameter changes by optimizing the developing voltage parameters (reducing AC voltage amplitude and adjusting DC voltage) to suppress carrier development at high processing speeds (250 mm/sec or more). This allows the system to maintain high productivity while preventing the harmful carrier development effect.
3Duration of action of stationary object
If the photosensitive layer thickness is increased to extend lifespan, then the lifespan is improved, but discharge unevenness and drum ghost occur due to narrow operation window
Solution Approach 1:
The patent applies parameter changes by precisely controlling the developing voltage parameters (AC voltage amplitude and DC voltage) to prevent discharge unevenness and drum ghost artifacts. This optimization enables the use of thick photosensitive layers (40 μm or more) that extend lifespan while maintaining image quality free from these harmful effects.
4Object-generated harmful factors
If the AC voltage amplitude is reduced to suppress carrier development, then the carrier development is suppressed, but the developing performance may be affected
Solution Approach 1:
The patent applies parameter changes by simultaneously optimizing both AC voltage amplitude and DC voltage. By reducing AC voltage to suppress carrier development while carefully adjusting DC voltage to maintain adequate developing performance, the invention resolves the contradiction between suppressing harmful carrier development and maintaining reliable developing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances image quality and extends the lifespan of the photosensitive drums by optimizing developing conditions, particularly at high processing speeds.
Implementation Method 1
a charging device configured to charge a surface of the image carrying member
Implementation Method 2
an exposure device configured to expose the charged surface of the image carrying member to form an electrostatic latent image that is attenuated in charge
Implementation Method 3
a developing device configured to supply the toner in the two-component developer carried by the developer carrying member to the image carrying member, and to develop the electrostatic latent image into a toner image
Implementation Method 4
The developing-voltage power supply is configured to apply a developing voltage to the developer carrying member, the developing voltage being generated by superimposition of an AC voltage onto a DC voltage
Data Source
AI summary
An image forming apparatus includes: an image carrying member; a charging device; an exposure device; a developing device; a drive unit; a developing-voltage power supply; and a control unit. The developing device has a developer carrying member which is configured to carry a two-component developer containing a toner and a carrier. The developing-voltage power supply is configured to apply a developing voltage to the developer carrying member, the developing voltage being generated by superimposition of an AC voltage onto a DC voltage. The image forming apparatus has a first print mode in which an image carrying member is driven and rotated by a drive unit at a linear speed of 250 [mm/sec] or more. The image carrying member has a single organic-photosensitive layer as a photosensitive layer. The photosensitive layer has a layer thickness of 40 [μm] or more at start of use.